Salvatore Gallicchio

Bio: Salvatore Gallicchio is an academic researcher from University of Bari. The author has contributed to research in topics: Flysch & Pleistocene. The author has an hindex of 10, co-authored 34 publications receiving 339 citations.

Landscape response to tectonic and climatic forcing in the foredeep of the southern Apennines, Italy: insights from Quaternary stratigraphy, quantitative geomorphic analysis, and denudation rate proxies

Abstract: We present new data about the morphological and stratigraphic evolution and the rates of fluvial denudation of the Tavoliere di Puglia plain, a low-relief landscape representing the northernmost sector of the Pliocene-Pleistocene foredeep of the southern Apennines. The study area is located between the easternmost part of the southern Apennine chain and the Gargano promontory and it is characterized by several orders of terraced fluvial deposits, disconformably overlying lower Pleistocene marine clay and organized in a staircase geometry, which recorded the emersion and the long-term incision history of this sector since mid-Pleistocene times. We used the spatial and altimetric distribution of several orders of middle to late Pleistocene fluvial terraces in order to perform paleotopographic reconstruction and GIS-aided eroded volumes estimates. Then, we estimated denudation rates on the basis of the terraces chronostratigraphy, supported by published OSL and AAR dating. Middle to upper Pleistocene denudation rates estimated by means of such an approach are slightly lower than 0.1 mm yr-1, in good agreement with short-term data from direct and indirect evaluation of suspended sediment yield. The analysis of longitudinal river profiles using the stream power erosion model provided additional information on the incision rates of the studied area. Middle to late Quaternary uplift rates (about 0.15 mm yr-1), calculated on the basis of the elevation above sea level of marine deposits outcropping in the easternmost sector of the study area, are quite similar to the erosion rates average value, thus suggesting a steady-state fluvial incision. The approach adopted in this work has demonstrated that erosion rates traditionally obtained by quantitative geomorphic analysis and ksn estimations can be successfully integrated to quantify rates of tectonic or geomorphological processes of a landscape approaching steady-state equilibrium. Copyright © 2014 John Wiley & Sons, Ltd.

Horizontal to Vertical Spectral Ratio (HVSR) Measurements in the Area Damaged by the 2002 Molise, Italy, Earthquake

Abstract: Following the 2002 Molise, Italy, earthquake, we performed a set of horizontal to vertical spectral ratio (HVSR) measurements in the damaged area. We recorded microtremors in all the municipalities reaching VI on the Mercalli-Cancani-Sieberg intensity scale. To calibrate our measurements, we installed accelerometers in two of the most damaged areas. We wanted to study HVSR in an area that is geologically different from areas commonly affected by earthquakes in the Southern Apennines. We also wanted to avoid the damage-attraction effect: after a strong event, most researchers study site amplification just where most of the damage has occurred. They might not consider that different structure vulnerability may mask the true distribution of site amplification. We checked for a possible correlation between observed intensity and the average of the non-flat HVSR measured in each municipality. The significant correlation indicates that site amplification has played a role in the damage pattern observed.

A Mixed Bioclastic–Siliciclastic Flood-Tidal Delta in a Micro Tidal Setting: Depositional Architectures and Hierarchical Internal Organization (Pliocene, Southern Apennine, Italy)

Abstract: Tide-dominated depositional systems are very common in macro tidal and meso tidal settings. They are less developed in micro tidal marine areas where sediments are dispersed mostly under the effects of waves and currents. In some specific coastal settings, the influence of the dominant hydrodynamics can be reduced or attenuated by the presence of promontories forming engulfed sectors or by the occurrence of submarine passageways or straits. In these conditions, as well as in micro tidal settings, the tidal influence can be amplified, producing a significant signature in the sedimentary record. A number to tide-influenced deposits can be recognized in the Neogene of the Southern Apennine, Italy, although the Mediterranean area is characterized by minor tidal ranges. Spectacular exposure of middle to upper Pliocene deposits cropping out around Tricarico allows the analysis of the architecture and internal complexities of a mixed bioclastic–siliciclastic succession deposited in a thrust-top basin. Undulations forming along the hinge of an anticline favored the onset of seaway conditions, which produced hydraulic amplification of marine currents flowing towards the chain and subjected to tidal influences. The mixed deposits of Tricarico exhibit prominent large-scale, unidirectional cross stratification and a suite of additional dune- and ripple-bedded structures of various dimensions. Cross stratification can be subdivided into four hierarchical levels based on their increasing degree of internal complexity of different ranks (from first-order to fourth-order sets). Processes invoked for the formation of such a complex suite of larger- and smaller-scale sedimentary structures are related to cyclical events, such as high-frequency sea-level oscillations and tidal cycles of various durations. First-order sets are interpreted as produced by migrating subaqueous dunes along a SSW–NNE-trending seaway at water depths below the wave base. These sets exhibit bed-thickness vertical patterns which have been related to the influence of high-frequency base-level oscillations that occurred during dune accumulation, producing alternating stages of accelerating and decelerating currents. Second-order cross stratification has been interpreted to have formed by dunes with varying sinuosity, superposition, and flow conditions, under the effect of varying current strengths but constant sediment production. Formset successions were produced by large compound dunes and are considered as the expression of low-energy and decaying dune fields that developed during times of decreasing sediment transport. Cross lamination of third-order and fourth-order sets shows series of bundles and couplets of coarser and finer laminae which, at a different scale, recorded repeated cycles of tidal ranges of different amplitudes. These considerations allow us to propose an original depositional model represented by a flood-tidal delta, which questions the absence of macro tidal sedimentation within the purportedly micro tidal oceanographic setting of the Mediterranean during the Pliocene.

Seasonal variability in sea surface oceanographic conditions in the Aegean Sea (Eastern Mediterranean): An overview

Abstract: Seasonal variability and the spatial distribution of sea surface temperatures (SST) and salinities (SSS) are reviewed, in relation to the prevailing climatological conditions, heat fluxes, water budget and general water circulation patterns. Within this context, consideration is given to: sea surface temperatures; air temperatures; precipitation; evaporation; wind speeds and directions; freshwater (mainly riverine) discharges throughout the Aegean; and the exchange of water masses with the Black Sea and eastern Mediterranean Sea. The investigation of satellite images, covering a 6-yr period (1988–1994), has enabled a synthesis of the monthly sea surface thermal distribution to be established. The climate of the Aegean Sea is characterised by annual air temperatures of 16–19.5°C, precipitation of about 500 mm yr−1 and evaporation of some 4 mm d−1. The Aegean has a negative heat budget (approximately −25 W m−2) and positive water balance (+ 1.0 m yr−1), when inflow from the Black Sea is considered. During the summer, the (northerly) Etesians are the dominant winds over the Sea. Mean monthly sea surface temperatures (SST) vary from 8°C in the north during winter, up to 26°C in the south during summer. SST depends mainly upon air temperature; there is a month's delay between the former and latter maxima. The sea surface salinity (SSS) varies also spatially and seasonally, ranging from less than 31 psu, in the north, to more than 39 psu, in the southeast; lower values (< 25 psu) occur adjacent to the river mouths. SSSs present their maximum differences during summer, whilst during winter and autumn the distribution of SSS is more uniform. The overall spatial SST and SSS distribution pattern is controlled by: distribution of the (colder) Black Sea Waters; advection of the (warmer) Levantine Waters, from the southeastern part of the Aegean; upwelling and downwelling; and, to a lesser extent, but locally important, freshwater riverine inflows.

Orbital forcing of continental climate during the Pleistocene: a complete astronomically-tuned climatic record from Lake Baikal, SE Siberia

Abstract: A new composite BDP-96 biogenic silica record over the entire Pleistocene was generated by splicing BDP-96-1 and BDP-96-2 drill cores from Lake Baikal, crosschecked against a similar record from a nearby BDP-98 drill core. A new astronomically tuned age model is proposed based on correlating peak biogenic silica responses with the timing of September perihelia. This target is derived from analysis of regional climate proxy responses during the Holocene, the last interglacial and around paleomagnetic reversals. By resolving virtually every precessional cycle during the Pleistocene, the new age model represents a major improvement compared with previously reported Lake Baikal timescales. The astronomically tuned ages of the Pleistocene paleomagnetic reversals are consistent with published dates. The minimal tuning approach we used (precession only) has also aligned high signal power in a narrow obliquity band, confirming the strong presence of orbital forcing. There are also strong ca 100-ka scale cycles, but these are not aligned with the orbital eccentricity. Despite the location of Lake Baikal in a continental interior that is highly sensitive to insolation forcing, the tuned biogenic silica record reveals a consistent phase difference of −32° (ca 4 ka) relative to insolation in the obliquity band. An inherent lag embedded in a continental proxy record, not driven by global ice volume, is an intriguing finding. Another new observation is that long-term changes in sedimentation rates in Lake Baikal appear to be related to the amplitude of orbital forcing; both amplitudes and sedimentation rates undergo significant changes during MIS 24-MIS 19 interval corresponding to the Middle Pleistocene Transition. With potential for linking continental and marine climato-stratigraphies, the new Baikal record serves a new benchmark correlation target in continental Eurasia, as an alternative to June 65°N insolation and ODP-correlated timescales.